RE: Heng Long noob is disappointed.
At some point, it might be cheaper to just get a second tank to do your troubleshooting, and then either keep it, or sell it. I just got a HL Panzer III that worked OK out of the box, so take heart that they do work, you just have one with a problem. I just opened mine up to assess the room inside for some improvements, and to just poke around a bit, and everything looks straightforward. To be honest, I am not crazy about the start button either.